Illinois natural gas prices
Nicor's standard price: 33 cents per therm
This month's gas charge
A therm is one unit of heat from gas (therms on your bill). Your bill may call this price the Natural Gas Cost.
Plans that lock your price for 6 months or more, for a home that uses 800 therms a year. Fees are included. Cheapest first. The standard gas price changes every month, so the savings are only a rough guide.
1. Santanna Energy Services
For new customers only.
2. Spark Energy Gas, LLC
For new customers only.
3. Spark Energy Gas, LLC
For new customers only.
4. Constellation NewEnergy-Gas Division, LLC
5. IGS Energy
6. Ambit Illinois, LLC
For new customers only.
7. Constellation NewEnergy-Gas Division, LLC
8. Constellation NewEnergy-Gas Division, LLC
9. IGS Energy
10. Just Energy
For new customers only.
| Company | Price | Locked for | Monthly fee | Fee to cancel | A typical year |
|---|---|---|---|---|---|
| Santanna Energy ServicesNew customers only | 39.37 cents per therm | 12 months | None | None | About $51 a year more than the standard price |
| Spark Energy Gas, LLCNew customers only | 49.9 cents per therm | 12 months | None | None | About $135 a year more than the standard price |
| Spark Energy Gas, LLCNew customers only | 49.9 cents per therm | 6 months | None | None | About $135 a year more than the standard price |
| Constellation NewEnergy-Gas Division, LLC | 54.9 cents per therm | 24 months | None | None | About $175 a year more than the standard price |
| IGS Energy | 54.9 cents per therm | 12 months | None | None | About $175 a year more than the standard price |
| Ambit Illinois, LLCNew customers only | 55 cents per therm | 12 months | None | None | About $176 a year more than the standard price |
| Constellation NewEnergy-Gas Division, LLC | 56.9 cents per therm | 12 months | None | None | About $191 a year more than the standard price |
| Constellation NewEnergy-Gas Division, LLC | 58.9 cents per therm | 6 months | None | None | About $207 a year more than the standard price |
| IGS Energy | 61.9 cents per therm | 24 months | None | None | About $231 a year more than the standard price |
| Just EnergyNew customers only | 65.9 cents per therm | 60 months | None | None | About $263 a year more than the standard price |
Prices come from the State of Illinois's price list (Plug In Illinois) (plugin.illinois.gov). We check it every 2 hours. Judy looks at more than price: she checks your own bill, fees and where prices are going.
| Dates | Standard price |
|---|---|
| Sep 1 to Sep 30, 2026 | 33 cents per therm |
| Aug 1 to Aug 31, 2026 | 36 cents per therm |
| Jul 1 to Jul 31, 2026 | 36 cents per therm |
| Jun 1 to Jun 30, 2026 | 36 cents per therm |
| May 1 to May 31, 2026 | 36 cents per therm |
| Apr 1 to Apr 30, 2026 | 46 cents per therm |
| Mar 1 to Mar 31, 2026 | 49 cents per therm |
| Feb 1 to Feb 28, 2026 | 53.23 cents per therm |
It is the price you pay if you never picked another company.
Today it is 33 cents per therm. A therm is one unit of heat from gas (therms on your bill).
Your bill may call it the Natural Gas Cost.
It follows the market price of natural gas, so it changes every month.
Yes. Your gas stays on. Nicor still delivers your gas and sends your bill.
Only the price part of your bill changes.
You can go back to Nicor's standard price later. Check your contract for a fee to leave early.
Call the company you pick, or sign up on its website. You don't call your utility.
Have your Nicor bill ready. The company will ask for a number from it.
Look for your account number near the top of your bill. Ask the company which number it needs.
The new company tells Nicor for you.
You have 10 business days to cancel for free after Nicor mails you a letter about the change.
Weekends and holidays don't count.
To cancel, call the new company, write to them or cancel online.
Watch your mail for a notice before your plan ends.
Read it closely. Many plans start again on their own.
Come back to Judy Saves when the notice comes. We will check your choices again.